Due to superior detergency and good usability, synthetic detergents in the washing of clothes have gained overwhelming support. However, not all of the gains to consumers from synthetic detergents are positive. For example, issues have recently begun to be raised regarding adverse affects on aquatic organisms from synthetic detergents including the possibility of being an endocrine disrupting chemical. Also, the fact cannot be escaped that a substantial amount of surfactant included in synthetic detergents remains on clothes despite repetitive and careful rinsing, nor may the probability be denied that such surfactant passes through the skin to bring about any number of affects on the human body.
While excellent washing performance through the surfactant is widely acknowledged, appearance of a new detergent having no added surfactant, yet having the same or greater washing performance and usability as synthetic detergents has been awaited when considering the adverse affects on organisms and the environment.
With this technical background, the applicant of the present invention proposes a detergent composition and a washing method using the same; wherein the detergent composition does not effectively use surfactant, has the same or greater washing performance and usability as conventional synthetic detergents that use a surfactant as a main component for detergency, and uses an alkaline buffer as the main component for detergency (Patent Reference 1).
However, the invention of Patent Reference 1 does not disclose or even suggest to the effect of using an organic chelating agent as the main component for detergency. Furthermore, the invention of Patent Reference 1 is completely different from the present invention, which uses an organic chelating agent as the main component for detergency, even in view of the fact that Patent Reference 1 describes to the effect of almost contradicting combination with the organic chelating agent in paragraph 0043 of the patent specification, saying ‘In this manner, since the principle component of this detergent reacts with hardness components, which are detergency constraints, and destroys them, a useful water-softening effect may be acquired without particularly adding an organic chelating agent, normally used as a synthetic detergent component, and a water-softening agent such as water-insoluble zeolite.’
Furthermore, Patent Reference 2 describes to the effect of washing clothes under specific high-alkali, low hardness washing conditions for the purpose of providing a washing method with low surfactant concentration and excellent detergency.
However, Patent Reference 2 merely discloses a washing method assuming use of a surfactant, and does not disclose or even suggest to the effect of washing using a washing liquid not including a surfactant as with the present invention.
Patent Reference 1: Japanese Patent Publication No. 3481615
Patent Reference 2: Japanese Unexamined Patent Application Publication No. Hei 9-132794
An objective of the present invention is to provide a detergent composition and a washing method using the same; wherein the detergent composition does not use surfactant that is questionable in terms of safeness on the human body and reduction in environmental burden, and uses an organic chelating agent as the main component for detergency, allowing the same or greater washing performance and usability as the synthetic detergents that use a conventional surfactant as the main component for detergency.